ERYTECH Pharma (Paris:ERYP) (ADR:EYRYY) (Euronext Paris - ERYP), a
clinical-stage biopharmaceutical company developing innovative therapies
by encapsulating therapeutic drug substances inside red blood cells,
today announced the presentation of the full data from its Phase 2b
study evaluating eryaspase (GRASPA®) in
combination with chemotherapy for the treatment of metastatic pancreatic
cancer. The open-label, multi-center, randomized Phase 2b clinical study
met its co-primary endpointsand demonstrated significant
improvement in both overall survival (OS) and progression-free survival
(PFS). The results will be presented during the European
Society for Medical Oncology (ESMO) Annual Meeting in Madrid.

The Phase 2b study evaluated eryaspase, L-asparaginase encapsulated in
red blood cells, as a second-line treatment in combination with
chemotherapy in 141 patients suffering from metastatic pancreatic
cancer. In this study, conducted in France, eryaspase was added to the
current standard of care (gemcitabine or FOLFOX) and compared to the
standard of care alone in a 2-to-1 randomization. Approximately 90% of
patients received gemcitabine. Baseline characteristics and patient
demographics were similar between the two treatment groups.

As reported in topline results earlier this year, the study met its
co-primary endpoints of OS and PFS with Hazard Ratios (HR) below 0.85 in
patients with no or low asparagine synthetase expression (ASNS 0/1),
approximately 70% of the study population, and demonstrated
statistically significant improvements of OS and PFS in the entire
patient population. The associated sensitivity analyses and subgroup
evaluations indicate the consistent treatment benefit with eryaspase
across the treated populations.

Principal Investigator Professor Pascal Hammel,
gastroenterologist-oncologist and head of the Oncology Unit at Beaujon
Hospital in Paris, commented, “The full results of this study are
highly encouraging and support eryaspase as a potential treatment option
for patients with metastatic pancreatic cancer in the second-line
setting.”

Highlights of the study results include:

Co-primary endpoints met:

HR of 0.65 for OS and 0.72 for PFS in the ASNS 0/1 patient
population

Statistically significant improvement of OS and PFS in the entire
patient population:

ORR of 11.6% in the eryaspase arm vs. 6.5% in the standard of
care arm

DCR of 47.4% in the eryaspase arm vs. 23.9% in the standard of
care arm

Patients with high ASNS-expressing tumors (ASNS2/3) had a worse
prognosis, but also a better relative treatment benefit:

HR of 0.45 for OS and 0.38 for PFS

DCR of 51.7% in the eryaspase arm vs. 7.1% in the standard of
care arm

The toxicity profile was similar in the two treatment arms:

The percentage of patients with at least one Grade 3 or 4
adverse event (AE) was 77% in the eryaspase-treated arm
compared to 86% in the control arm. The most common Grade 3 or
4 AEs were: increased gamma-glutamyl transferase (17% vs.
25%), neutropenia (13% vs. 11%), general health deterioration
(13% vs. 2%), and thrombocytopenia (10% vs. 7%), respectively.

The percentage of patients with at least one serious adverse
events (SAE) was 45% in the eryaspase-treated arm compared to
50% in the control arm. The most common SAEs were: general
health deterioration (9% each), gastro-intestinal hemorrhage
(2% vs. 7%, respectively).

Dr. Iman El-Hariry, Chief Medical Officer of ERYTECH, stated, “Despite
intense research efforts, limited progress has been made toward
increased overall survival and metastatic pancreatic cancer remains a
high unmet medical need.We are quite impressed with this study
outcome, particularly with the overall survival advantage demonstrated
in the eryaspase arm. These results underscore the importance of
targeting the metabolic pathways in pancreatic cancer and potentially
other solid tumors.”

“We are very pleased by the results from this landmark study. The
full picture emerging from these data shows a robust clinical benefit in
this particularly difficult-to-treat and highly morbid form of cancer,”
said Gil Beyen, Chairman and CEO of ERYTECH. “Eryaspase adds an
entirely new mode of action to the fight against this terrible disease
and opens avenues to other solid tumor indications. We are working with
the regulatory agencies to develop a Phase 3 plan in pancreatic cancer,
and we are exploring other solid tumor indications for our product
candidate.”

The full poster presentation will be accessible on September 8, 2017
within the “Investors” section of ERYTECH’s website at www.investors.erytech.com.

ERYTECH will also host an investor and analyst event on Monday,
September 11 at 6:15 p.m. CEST at ESMO 2017, in Madrid. Pre-registration
for the live event at ESMO 2017 is required. To RSVP, please contact
Janhavi Mohite at jmohite@theruthgroup.com.

For those unable to attend, a live webcast will be accessible at the
start of the event starting at 06:30pm CEST, and is available for
replay on the “Investors” of the ERYTECH’s website at http://erytech.com/webcast.html.

About pancreatic cancer:

Pancreatic cancer is a disease in which malignant (cancer) cells are
found in the tissues of the pancreas. Every year, there are
approximately 150,000 new cases of pancreatic cancer diagnosed in Europe
and the United States. Pancreatic cancer is a particularly aggressive
cancer, with a five-year survival rate of approximately 9%. It is
currently the fourth leading cause of cancer death in the United States
and is projected to rise to the second leading cause by 2030. Limited
therapeutic options are currently available for this indication, thereby
reinforcing the need to develop new therapeutic strategies and rational
drug combinations with the aim of improving overall patient outcomes and
quality of life.

About ERYTECH and eryaspase (GRASPA®): www.erytech.comFounded
in Lyon, France in 2004, ERYTECH is a clinical-stage biopharmaceutical
company developing innovative therapies for rare forms of cancer and
orphan diseases. Leveraging its proprietary ERYCAPS platform, which uses
a novel technology to encapsulate therapeutic drug substances inside red
blood cells, ERYTECH has developed a pipeline of product candidates
targeting markets with high unmet medical needs. ERYTECH’s initial focus
is on the development of products that target the amino acid metabolism
of cancer, depriving them of nutrients necessary for their survival.

The company’s lead product, eryaspase, also known under the trade name
GRASPA®, consists of an enzyme, L-asparaginase, encapsulated
inside donor-derived red blood cells. L-asparaginase degrades
asparagine, a naturally occurring amino acid essential for the survival
and proliferation of cancer cells. L-asparaginase has been a standard
component of multiagent chemotherapy for the treatment of acute
lymphoblastic leukemia (ALL), but side effects limit treatment
compliance, especially in adults and patients with weak performance
status. With its improved safety profile, eryaspase aims to provide
L-asparaginase to patients who cannot tolerate current non-encapsulated
asparaginases.

Eryaspase demonstrated positive efficacy and safety results in different
studies in ALL, including in a Phase 2 study in elderly patients with
ALL, and a Phase 2/3 study in children and adults with relapsed or
refractory ALL. The positive results of its Phase 2b clinical trial in
second line metastatic pancreatic cancer mark a first step in solid
tumors. ERYTECH also has an ongoing Phase 1 clinical study of eryaspase
in the United States in adults with newly diagnosed ALL, and a Phase 2b
clinical study in Europe in elderly patients with newly diagnosed acute
myeloid leukemia (AML), each in combination with chemotherapy.

ERYTECH produces eryaspase at its own GMP-approved and operational
manufacturing site in Lyon (France), and at a site for clinical
production in Philadelphia (USA). ERYTECH has entered into licensing and
distribution partnership agreements for eryaspase for ALL and AML in
Europe with Orphan Europe (Recordati Group), and for ALL in Israel with
TEVA, which will market the product under the GRASPA® brand
name. The European Medicines Agency (EMA) and the U.S. Food and Drug
Administration (FDA) have granted orphan drug designations for eryaspase
for the treatment of ALL, AML and pancreatic cancer.

In addition to eryaspase, ERYTECH is developing two other product
candidates that focus on using encapsulated enzymes to target cancer
metabolism and induce tumor starvation. ERYTECH is also exploring the
use of its ERYCAPS platform for developing cancer immunotherapies and
enzyme replacement therapies.

ERYTECH is listed on Euronext regulated market in Paris (ISIN code:
FR0011471135, ticker: ERYP) and is part of the CAC Healthcare, CAC
Pharma & Bio, CAC Mid & Small, CAC All Tradable, EnterNext PEA-PME 150
and Next Biotech indexes. ERYTECH is also listed in the U.S. under an
ADR level 1 program (OTC, ticker EYRYY).

Forward-looking information

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